This invention relates to a method of, and an arparatus for, controlling the dispensing of money in the form of units having a plurality on denominations. The invention is particularly, but not exclusively, applicable to machines such as vending machines which receive coins of a plurality of denominations, and which have a plurality of stores each containing coins of a respective denomination, and each possibly being capable of being replenished by insertion of coins into the vending machine. Means are provided for dispensing coins from the stores in an amount which corresponds to the difference between the amount inserted, and the value of the vend or vends performed by the machine.
The invention is not limited to such arrangements. The dispensed monetary units could be, for example, banknotes, or a mixture of banknotes and coins. The invention also has wider applicability than vending machines; it may be applied to change-giving machines of any type.
In the field of vending machines, it is well known to use a dispensing control means which calculates a preferred combination of coins for dispensing in the form of change. The typical way of achieving this, referred to as the "least number of coins" method, involves using as many higer-denomination coins as possible, so that the total number of dispensed coins is minimised. This is intended to maximise the number of coins retained in the stores so that change remains available for the maximum number of transactions. Also, users of machines generally prefer their change in the form of fewer high-denomination coins.
GB-9216205.6 and PCT/GB93/01623 (referred to herein as the "earlier applications" and the cornents or which are incorporated herein by reference) describe a particularly efficient technique for determining the combination of monetary units to be dispensed.
In such systems, there is often a tendency for the apparatus frequently to dispense the same denomination. For example, in machines that have many products that can be vended at a vend price of 40p, users will often insert 50p or .English Pound.1 coins. Assuming that the machine can dispense a variety of different coin denominations, the "least number of coins" technique may result in the apparatus frequently selecting 10p, or a combination of a 50p and 10p, for dispensing as change. This reduces the number of available 50p and 10p coins for future change-giving operations. If for example the machine runs out of 10p coins, it may no longer be possible by using a large number of smaller-denomination coins which is less desirable from the point of view of the machine user.